Specialized Hillbilly MTB Tire Review



Review by Dario DiGiulio

Mud tires are one of those products that nearly every tire brand seems to carry, but that you rarely see out in the real world. Obviously, they see use on World Cup bikes in the right situations, but how many riding buddies do you have that regularly swap out for a mud spike when things get a little bit sloppy? In pursuit of making their already multipurpose mud offering a little more well-rounded, Specialized has updated the Hillbilly to round out their new rubber lineup. The new Hillbilly still holds its own when conditions are nasty, but is it good enough to warrant a swap for regular use?


One of the nice updates we’re seeing in Specialized’s new tire lineup is a greater simplicity in the offerings and naming conventions. That carries through to the new Hillbilly, which comes in only two flavors: Grid Trail T9 and Grid Gravity T9. They both carry the “2Bliss” moniker, which is only meant to imply their tubeless compatibility (something of a given at this point). T9 indicates the rubber durometer, which in this case is Specialized’s softest option, offering the best grip on slippery and wet terrain, as well as the highest rolling resistance.

The two casing options, Grid Trail and Grid Gravity, are easily differentiated and well named for the tasks at hand. Trail is a 60 TPI single ply construction with bead-to-bead puncture protection, aimed at hard riding in most conditions, while sporting a relatively low weight for how sticky the rubber is. Gravity is focused on the harder-hitting end of the spectrum, with a two-ply construction meant to increase puncture protection and hold up better in hard cornering and g-outs.

At $75 each, the new Hillbilly carries a slightly lower cost than competitor’s offerings, like the Maxxis Shorty or the Schwalbe Magic Mary. More on how the Hillbilly compares to other offerings later on, but first let’s get to the ride impressions.

Specialized Hillbilly MTB Tire Review


Specialized describes the Hillbilly as “gravity-focused, excelling in steep, slippery, loose, and wet conditions in the continental north,” and my experience mirrors this almost exactly. The dig-in traction of the Hillbilly is nothing short of impressive, and I strongly agree with the continental north distinction. Up here in Bellingham, it’s been an unusually sloppy fall and winter, providing the perfect testing ground for these tires. We’re no strangers to rain, but things have been colder than is normal, leading to more freeze-thaw, snow, and mud. Combine those three factors, and you have a recipe for some pretty sketchy riding, assuming you’re the type to get out and play in the muck.

As someone who revels in nasty conditions riding, I’ve had plenty of time on a wide variety of tires, with the Hillbillies shaking out to be pretty high up on the bad-conditions list. Cornering feel is similar to a DHF-style pattern, with a very solid edge feel so long as you commit to it. As you’d expect, the tread doesn’t easily pack up, and sheds sticky soil far far better than something like an Assegai. Compared to another Specialized tire I’ve come to love – the Cannibal – the Hillbilly digs in a bit better when things aren’t leaned over, with the Cannibal favoring slightly firmer conditions and performing much better on hard packed trails. Hardpack is where I’ve been most surprised by the Hillbilly, as it’s impressively confident when things harden up. There is definitely more squirm than with tires more tailored to dry terrain, but like the new Continental Argotal it holds its own, meaning you won’t want to take it off as soon as the trails start to dry out. One area where it does fall short is in gravelly terrain, as anything that can roll under the tire seems to kick it out faster than designs with more knob surface hitting the ground at any given point. The Hillbilly is not the tire for that situation, but that’s why we have choices!

Specialized Hillbilly MTB Tire Review

Compared with the stickiest MaxxGrip rubber from Maxxis, Specialized’s T9 compound is only a hair behind. On wet roots and slimy rocks, there’s just a tiny bit more smearing power with the Maxxis stuff, but it’s by no means a massive difference. Strangely, it feels like the T9 compound is more consistent when things are really cold, maintaining its feel when other tires start to turn wooden and too firm. This could also be aided by the casing construction, which has a great ride feel, similar to the less robust but very comfortable Continental DH casings. Grid Gravity, which is the DH-focused moniker in the Specialized catalog, feels a bit more supple than the DH offerings from Schwalbe or Maxxis, but holds up to hard cornering and square impacts very well. I’ve regularly been able to run 19psi in the slop, without smashing rim on any square edge hits. In drier conditions, pressures in the low 20s feels great, still offering enough support for most trails.

Contrary to the mud spike design influence, I ran the Hillbilly at the dry and dusty height of this past Summer, when dirt was about as powdery and loose as possible. While something like an Assegai handles these conditions better overall, I wanted to see if a “cut spike” style tire offered anything different – and came away pretty impressed with how well the big blocky tire out front performed when cornering and braking. I even ran it as a rear for a while, but the rolling resistance is better suited to ebikes or shuttle-only bikes, as climbing really suffered. Dry-focused tires like the Assegai, Cannibal, or Kryptotal Fr are obviously going to best any cut spike design when things aren’t sloppy, but when the rain is coming down, the Hillbilly is on my short list of tires to grab.

The Wolf’s Last Word

If you regularly ride the steep and deep trails that seem to evolve with every lap, then you know the value of a front tire that can hold a line when the dirt doesn’t want to stay put. The Specialized Hillbilly excels in that terrain, and whenever the conditions are foul – be it snow, mud, or soggy loam. Thanks to the staggered edge knobs and excellent rubber compound, leaning the tire inspires confidence, and the grip feels consistent and predictable.

Price: $75.00

29” Gravity: 1,340g | 29” Trail: 1,070g
27.5” Gravity: 1,240g | 27.5” Trail: 985g

Website: Specialized.com

We Dig

Excellent loose soil grip
Predictable cornering
Comfortable and sturdy DH casing

We Don’t

Slow-rolling in the rear
Slightly squirmy on roots and rocks
Sketchier on gravelly corners


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